"Riding your Computer Up" vs. "Lite Deco"

[Basking Ridge Diver]

Is this your local dive boats? I have noticed over the years that the Florida boats seem to have loosened the no deco rule. Its still part of the predive briefing but not enforced as long as you meet the time requirement. Also possibly a bit of don't ask, don't tell. Its also possible that the increase in the number of divers with "conservative" algorithms as brought an adjustment in boat attitudes.

Yep local dive boats I have been on. One was ridiculous - wanting to see your dive computer when you came up. That was the last time I used them... BA (Bad Attitude) for a crew - but to be fair they sit you down for a number of reasons...

I had a buddy come up to the surface feet first - that was it for him... lol - I was not there but I find that very amusing - he was diving an Al 149 and he was not weighted for it. So when he got it down to 800psi or so it flipped him upside down and he went slowly to the surface upside down...

 

[DevonDiver]

My training did not train me to pick a computer for longer bottom time, but neither did it train me to not do that. It simply trained me to use a computer and left the choice of computer completely up to me.

At this stage.. and relevant to some of the posts on this thread.... it's worth remembering what IS taught for recreational computer use:

1. Dive conservatively within no-stop limits of the computer.

Follow the most conservative computer. Surface or ascend when either computer - yours or your buddy's - approaches its no decompression limit. If you follow the least conservative. you're in effect sharing that computer, which you shouldn't do.​

2. Limit dives to the most conservative computer in a group. i.e. ascend when the first computer indicates no remaining no-stop bottom time. (would include a single diver wearing 2 computers).

Computers are sophisticated calculators with depth gauges and timers that calculate theoretical nitrogen in the body. They're no more or less valid than dive tables and they don't track anything physical in your body. The recommendations for conservative diving with tables apply to computer diving.​

Plan cold/strenuous dives with the RDP as though the depth were 4 metres/10 feet deeper than actual. With a computer, be conservative using the most appropriate method for your computer.
​

The observant will notice how many times the word 'conservative' is used. There's no ambiguity in that, and no context for interpreting training to advocate using multiple computers/tables to extend bottom time, shopping around for the least conservative options or going into deco for any reason other than an emergency.

Going beyond the agencies recommendations (as most agencies advice on computers is to simply RTFM and follow those instructions).... are there any computer manufacturers whose manuals state that a diver should exceed no-stop limits without appropriate training? Nope

Are there any manuals that suggest 'hacks' to extend bottom-time? Or to dive multiple computers and disregard the least aggressive etc etc? Nope

Do computer manuals explain how and when to make use of extra conservatism settings? Yep

Of course, agencies generally don't dictate choices of computers, nor make recommendations on computer algorithms. They don't need to, because computer manufacturers do a good job of explaining proper usage...and are quite explicit in promoting conservative use and not exceeding no-stop limits.

 

[uncfnp]

Yep local dive boats I have been on. One was ridiculous - wanting to see your dive computer when you came up. That was the last time I used them... BA (Bad Attitude) for a crew - but to be fair they sit you down for a number of reasons...

I had a buddy come up to the surface feet first - that was it for him... lol - I was not there but I find that very amusing - he was diving an Al 149 and he was not weighted for it. So when he got it down to 800psi or so it flipped him upside down and he went slowly to the surface upside down...

That's way more babysitting then I am willing to tolerate at this stage in my life and I am surprised to hear about this on Jersy dive boats. Like you, it would be my last dive with that crew.

 

[Basking Ridge Diver]

That's way more babysitting then I am willing to tolerate at this stage in my life and I am surprised to hear about this on Jersy dive boats. Like you, it would be my last dive with that crew.

Agreed - I now use several private boats during the summer and on occasion I use the bigger boats to hit locations that are further off shore and deserve a bigger boat.

 

[lermontov]

At this stage.. and relevant to some of the posts on this thread.... it's worth remembering what IS taught for recreational computer use:

1. Dive conservatively within no-stop limits of the computer.

Follow the most conservative computer. Surface or ascend when either computer - yours or your buddy's - approaches its no decompression limit. If you follow the least conservative. you're in effect sharing that computer, which you shouldn't do.​

2. Limit dives to the most conservative computer in a group. i.e. ascend when the first computer indicates no remaining no-stop bottom time. (would include a single diver wearing 2 computers).

Computers are sophisticated calculators with depth gauges and timers that calculate theoretical nitrogen in the body. They're no more or less valid than dive tables and they don't track anything physical in your body. The recommendations for conservative diving with tables apply to computer diving.​

Plan cold/strenuous dives with the RDP as though the depth were 4 metres/10 feet deeper than actual. With a computer, be conservative using the most appropriate method for your computer.
​

The observant will notice how many times the word 'conservative' is used. There's no ambiguity in that, and no context for interpreting training to advocate using multiple computers/tables to extend bottom time, shopping around for the least conservative options or going into deco for any reason other than an emergency.

Going beyond the agencies recommendations (as most agencies advice on computers is to simply RTFM and follow those instructions).... are there any computer manufacturers whose manuals state that a diver should exceed no-stop limits without appropriate training? Nope

Are there any manuals that suggest 'hacks' to extend bottom-time? Or to dive multiple computers and disregard the least aggressive etc etc? Nope

Do computer manuals explain how and when to make use of extra conservatism settings? Yep

Of course, agencies generally don't dictate choices of computers, nor make recommendations on computer algorithms. They don't need to, because computer manufacturers do a good job of explaining proper usage...and are quite explicit in promoting conservative use and not exceeding no-stop limits.

that pretty much covers it and theres plenty of caveats to steer to the lowest ( most conservative) common denominator, i doubt if you could argue that this is a common sense approach to divers with little or no understanding deco issues. My irritation is the way exceeding NDL is handled in introductory classes creating a terror that exceeding NDL is a near death experience when as you get more understanding its not as cut and dried as you were first taught.
I sat in on my daughters OW class recently and the instructor stated "never ever ever under any circumstances go past your NDL"
I like the shearwater manual warning ( in regard to PPo2 configurations)and is a much better approach in my view
"Do not change these values unless you understand the effects"
Bring this approach into the classrooms and it would help bridge the (mindset) gap between rec and tech diving and make for a more informed rec diver- might increase the tech diving population too- just think more gear sales more instruction course

 

[lowviz]

... My irritation is the way exceeding NDL is handled in introductory classes creating a terror that exceeding NDL is a near death experience ...

I sat in on my daughters OW class recently and the instructor stated "never ever ever under any circumstances go past your NDL" .../...

Tell her to not to get overly concerned. In computer class, she gets to pick her own NDL.

 

[DevonDiver]

My irritation is the way exceeding NDL is handled in introductory classes creating a terror that exceeding NDL is a near death experience [...] I like the shearwater manual warning and is a much better approach in my view

You mean this "non-dramatic" guidance?

"Do not change these values unless you understand the effects"

When considering Open Water divers...who typically receive 4 dives of training, normally over 2-4 days.... How much understanding should we presume?

Sure, it'd be nice to transparently and comprehensively explain the nitty-gritty details of no-stop versus decompression diving risk...

....but for so long as the student has opted for the shortest, least comprehensive training available.... that 'luxury' doesn't fit the price tag.

In the time available (paid for)... they get the short explanation: "Don't exceed NDL, because it's dangerous".

Nobody is prevented from seeking more comprehensive training, enabling more detailed and explained knowledge to be delivered..... that's the consumer's choice.

Beyond entry-level training, the scope of understanding should/could be progressed. See my post here:
Redundancy Required for Decompression Diving?

 

[lermontov]

You mean this "non-dramatic" guidance?

When considering Open Water divers...who typically receive 4 dives of training, normally over 2-4 days.... How much understanding should we presume?

In the time available (paid for)... they get the short explanation: "Don't exceed NDL, because it's dangerous".

well you could combine all of the above
Don't exceed NDL, because it's potentially dangerous until you have much better understanding and your risking your life if you down get suitable training

that would be more transparent I dont think it needs going in to the nitty griity just give them an honest answer instead, why continue this parent /child relationship treating people like little children

 

[lermontov]

Tell her to not to get overly concerned. In computer class, she gets to pick her own NDL.

funny man...

 

[DevonDiver]

Don't exceed NDL, because it's potentially dangerous until you have much better understanding and your risking your life if you down get suitable training

What's "potentially" dangerous about exceeding an NDL when your sum knowledge and ability is derived from the PADI Open Water course?

It's just plain dangerous.

"Risking your life" implies a modicum of danger, does it not?

Would you warn your kids that playing on train tracks could kill them? Or would you 'empower' them with transparency and teach them it's ok to play on train tracks if they "understood" that trains run on a timetable?

It's not true to say that agencies, even PADI, say "never" exceed NDL... there's copious advertising for the training programmes that enable extended no-stop and decompression diving.

The message is clearly: at this training level exceeding no-stop limits is dangerous, so don't do it.